Gun control apparatus



Dec. 18, 1951 J. L. BORDEN, JR 2,578,666

GUN CONTROL APPARATUS Filed Jan. 51, 1946 7 Sheets-Sheet l M I A5 alEcrae PEEDICTOB 7 w REFERENCE STAKE} F 28 JUE|EPHL EDRDEN;LTR.,

Dec. 18, 1951 BQRDEN, JR 2,578,666

GUN CONTROL APPARATUS Filed Jan. 31, 1946 7 Sheets-Sheet 2 AZ/MUTH 45- ELEVATION AZ/MUTH AMPLIFIER AMPL/F/ER GUN L/U/VCTYO BOX 40 4 mam? 5 7 Box GENEEATOE UNIT PEED/CTOE Dec. 18, 1951 J. L. BORDEN, JR 2,578,666

GUN .CONTROL APPARATUS Filed Jan. 51, 1946 7 Sheets-Sheet 4 JUEEF HL-EH:1R

Dec. 18, 1951 .1. L. BORDEN, JR 2,578,665

GUN CONTROL APPARATUS Filed Jan. 31, 1946 7 Sheets-Sheet 5 OUTPUT l SIGNAL 6 INPUT A /MUTH RECEIVER SERVO PHASE CTI/VG CIRCUIT n MWwJAMW W Dec. 18, 1951 J. BORDEN, JR 2,578,666

GUN CONTROL APPARATUS Filed Jan. 31, 1946 7 Sheets-Sheet 6 /87 ,ELEVATION RECEI vs/a SE12 vo.

ELEVATION SERVO AMPLIFIER SIGNAL INPUT 96 7555; A. BOR05N, 75

%Mw2m Dec. 18, 1951 J. 1.. BORDEN, JR 2,578,666

GUN CONTROL APPARATUS Filed Jan. 31, 1946 7 Sheets-Sheet 7 TWO P/l/YSE MOTOR.

INPUT I II 242 a grwwvbod Patented Dec. 18, 1951 UNITED STATES TENT OFFHCE (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. 'G. .757.)

23 Claims.

The invention described herein may be manufactured and used by orfor the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to a method of and apparatus for aiming one or more guns to move them in train and elevation in themanner necessary to continuously engage a moving target which may be visible or invisible from the gun location.

At the present time, guns of large caliber are aimed at moving targets such as aircraft or surface ships, on the basis of data suppiied by a gun fire director or computer. Such directors are constructed to receive various input data such as the present range, angular rates ofmovement of the target in azimuth and elevation, altitude, etc., and to supply as outputs, the continuously changing azimuth and elevation angles and fuse settings to which the gun or guns and projectiles should be adjusted in order to hit the target. The guns are usually located at some distance from the director and it is customary to supply the director outputs or computed data to the guns by telephone or by telemetric transmission systems.

In case the necessar information is conveyed by telephone, there is an appreciable time lag of approximately seconds between the time the information is received at the .guns and the time such information can beset into the guns and the guns fired. Furthermore, such systems involve the serious possibility oferrors caused by incorrectrepetition of director valuesby the-personnel at the director, or misunderstanding on the part of the personnel at the guns.

In event the data are supplied by telemetric. transmission systems, the valuesof elevation and azimuth are read oi? on repeaters .at the guns and used as the oasis for manual adjustments of the guns. This may be clone by conventional match the pointer systems wherein the gun trainer, for example, operates the training handwheel of his gun untilapointer controlled thereby matches, or is in a predetermined position with respect to, a pointer actuated by the: train repeater. Or, in other systems, the train and elevation repeaters at each gun may directly control a source of power, through well-known servo-motor or follow-ups, to automatically cause the gun to be elevatedand trained in accordance with computations supplied by-the director. In

such systemsthere is either the possibility of a lag :introduced betweenthe timethepointer and trainer notice a movement-enticedirector-controlled pointers and the time they are able to match said movement by actuation of their respective hand wheels; or a time lag is introduced by mechanical and electrical adjustments and inertia of the follow-up controls.

The output values of angles of the director are, of course, with reference to apredetermined plane and reference line. That is to say, for example, its output elevation angle will be with reference to a horizontal plane and its output azimuth angle will be with reference to a horizontal line having a preselected direction such as north-south. .In order that the gun may be properly aimed, the angular valuesof elevation and train imparted thereto must be measured from a plane and a line that are parallel to those ;of the director. This requires that, prior to :the commencement of firing, the gun and its director be coordinated LOn-the other hand, any subsidence settling or shifting of the gun-during firing, willalter the reference plane and/or reference line of the gun with relation to the director so that, as a result, the gun will not be correctly aimed when subsidence takes place with theprior 'artsystems j ust discussed.

It is therefore .an object of my invention to providea systemof trainingand elevating a gun or guns by information supplied by a remote director and wherein the foregoing drawbacks and-possibilities of-error are obviated.

.Arfurther objectisto provide a method of and apparatus for correctly aiming a gun wherein the :gun is smoothly and continuously moved in train :andpelevationso .as to at all times remain in substantially correct'firing position and -may continuousl engage the target.

Another object is to provide a method of, and apparatus for aiming a gun wherein the time between shots may be very appreciably reduced over that required by present comparable systems, while, at the same time, effecting a very substantial increase in accuracy and percentage of hits upon the moving target.

A still further-objectis to provide a'method of, and apparatus for aiming a gun or guns whereinthe possibility-of-errors that might otherwise be caused by settling or displacement of the gun due to its-own-weight, recoil in firing, etc, is avoided and the-gun is, at alltimes, smoothly and correctlyaimed solely upon the basis of data supplied by the director.

A further object is to provide an improved system of gun aiming wherein the gun is -con tinuously trained to retain a sight carriedthereby with its line of sight directed upon a fixed reference stake or dummy target as the line of sight is automatically moved in azimuth relatively to the gun at a rate automatically effected and controlled by the director.

Another object is to provide a system of aiming a gun wherein the elevation quadrant is smoothly and automatically pivoted relatively to the gun so that the correct elevation may be obtained by the simple act of continuously changing the elevation of the gun and quadrant as a unit, to maintain centered, the bubble or other indicating element of a longitudinal level carried by said quadrant.

A still further object is to provide an alternative and satisfactory means for training the gun when, for any reason, the fixed reference stake becomes obscured.

Another object is to provide improved elevation and azimuth receivers whereby increased accuracy of reception of signals from the director is assured.

Other objects and advantages of the invention will become apparent as the description proceeds.

In the drawings:

Figure 1 is a plan view showing diagrammatically a typical arrangement of gun, director, aiming point and target.

Figure 2 is an elevation of the right-hand side of the gun showing themanner in which the elevation quadrant and gun are rotated in opposite directions to maintain the gun continuously at proper elevation.

Figure 3 is a schematic View of a portion of the electrical connections between the various units utilized in my invention and showing how a battery of four guns may be simultaneously controlled from a single director.

Figure 4 is a perspective view of a portion of the left side of a 155 mm. gun equipped for control by apparatus and in accordance with the method of my invention and showing more particularly the azimuth or train control.

Figure 5 is a perspective view showing a portion of the right hand or elevation side of a 155 mm. gun equipped for control in accordance with the apparatus and method forming the subject matter of my invention.

Figure 6 is a schematic view of the electrical connections for azimuth control between the director and gun and showing the mechanical drive from the servo-motor to the revoluble head of the azimuth sight and the rotor of the receiver at the gun. This figure also shows the indicator which may be used for training when the aiming stake becomes obscured.

Figure 6A is a schematic view of the electrical connections from the director to the elevation side of the gun and showing the manner in which the servo-motor is mechanically connected to drive the elevation quadrant of the gun and the elevation receiver.

Figure 7 is a wiring diagram showing one of the hook-ups by which a transmitter at the di-v rector controls a respective servo-motor at the gun.

Figure 8 is a perspective view showing the synchronizer of the azimuth control which acts to prevent ambiguity in the angular values repeated by the fine azimuth receiver and servomotor controlled thereby.

Figure 9 is a detail view of the contacts of the synchronizer..

Principles of operation Referring to Figure 1, the numeral I identifies a gun emplacement or base on which a rotatable gun carriage or platform 2 is rotatable about a central vertical axis normal to the plane of the paper. Teeth 3 are formed on the periphery of platform 2 and with which a worm 4 is adapted to mesh. The worm is journaled on base I on a horizontal axis, by means of a shaft 5 and bearing 6. A handwheel I is secured to shaft 5 and is in a position such that it may be turned by an operator while looking into the eye-piece 8 of azimuth telescope 9. This telescope is of the well-known panoramic type including an objective I I rotatable relatively to the gun about a normal vertical axis and having optical parts by which the image of objects in the line of sight determined by said objective, is deflected to a horizontally-positioned ocular. A gear It is connected to rotate objective I I about its vertical axis. As it is so rotated, to an observer looking in ocular 8, objects appear to move laterally across the field of view in a direction depending upon the direction of rotation of objective I I.

A worm I2 is in mesh with gear I0 and is adapted to be driven by a servo-motor Is that is electrically connected with, and controlled by, a director I4, through electrical circuit connections I5. This director has means such as sights or radar, for determining a line I8 between director I4 and target T which is assumed to be traveling in the direction indicated by the arrow.

The gun I1 is journaled for elevation about a normally horizontal axis, by trunnions I8 supported in bearings in standards I9 fixed to platform 2. See Figure 2. Elevation is eifected by an arcuate rack 20 attached to the gun cradle 2| and in mesh with a Worm 22 journaled in standards I9 and adapted for actuation by a handwheel 23. A servo-motor 24 similar to motor I3, is carried by cradle 2| and is connected to, and controlled by, director I4, through electrical cable 25. This motor has a worm 26 on its shaft, in mesh with the arcuate rack of an elevation quadrant 27 having a bubble tube level 28, or other level indicating means supported thereon. Quadrant 21 is supported on cradle 2H for pivotal movement about an axis parallel to the axis of trunnions I8.

In operation, a dummy target or reference stake 29 is provided at any convenient position, easily observable from the gun, and the director and gun are coordinated so that the director output or predicted angle in azimuth, will be with reference to a base line that is parallel to the line of sight form telescope 9 to stake 29, while the director output or predicted angle in elevation, as well as the angle of gun elevation, will be with reference to a horizontal plane. Electrical connections are made between the gun and director, and, when a target is sighted, the director is so moved as to maintain line I6 directed thereon, either by direct sighting, radar, sound locators. or other known means. Other required values such as range, are introduced into the director which then supplies data in the form of predicted elevation and azimuth angles at which the gun should be adjusted in order to hit the target.

It is assumed that the target is moving, so that the aforesaid output angles are continuously changing in accordance with the targets speed and heading. Signals proportional to director output or prediction angle in azimuth are transe mitted over cables I5 to motor I3 so that the awe-pee latter is operated in accordance with the rate of change of said prediction angle. The motor then acts to-rotate abjective 9 about its Vertical axis in accordance with the aforesaid rate of change in the direction opposite to thedirection in which the gun must be moved. To the gun trainer, looking into ocular 8, stake 2E3 appears to move laterally away from the vertical cross hair of the telescope. He then continuously adjusts hand wheel '1' to maintain the cross hair superposedover a selected point of the target and, in so doing, causes the gun to be traversed at theproper rate predicted by the director.

At the same time, signals proportional to predicted elevation angle are transmitted from director l, over cable 25, to drive motor 24 in accordance with such signals. The motor is operated in a direction such that sector 27 will be rotated in thedirection opposite to the necessary direction of elevation or depression of the gun. Thus, for example, if the elevation of gun ll should increase, sector 2? will be rotated clockwise as seen in Figure 2. The gun pointer, noting the bubble of level 28 to move ofi center to the left, will rotate his hand-wheel 23 to keep the bubble at all times centered.

In this manner the gun is continuously properly aimed so that it may be fired at any time. Furthermore, shifting or subsidence of the gun itself has no effect upon the accuracy of fire since all angles are measured with reference to a line and a plane that are fixed with reference to space external of the gun and its support. For example, suppose that the gun shifts about a vertical axis or subsides in a vertical plane through the gun bore. Operation of hand wheel 1 in the manner necessary to restore the line of sight to the stake, and of hand wheel 23 to centralize the bubble, completely corrects for the errors in aim that would otherwise have been introduced. These errors would have remained uncorrected in prior art systems where the gun is moved simply to match one pointer with another, controlled in position by the director.

Director-gun electrical connections At Figure 3, I have shown a schematic layout of the connections between the director and the gun or guns. In this figure, the director or predictor M is coupled to a main junction box 30 by cable connectors 3| and 32, one of which supplies current to the predictor Hi from a generator unit 33 connected to box 30 by a connector 34. Box 35 is provided with outlets for connectors 35 and 3B.

Connector 35 leads to an extension junction box 37 having receptacles for apair of connectors 38 and '39, each of which may lead to a respective gun junction box, only one of which, 49, is shown upon the figure. It will be understood that connector 36 may lead to an extension junction box similar to 31 so that from one to four guns, as

desired, may be controlled from a single director.

Box 40 has a 19-hole receptacle for a connector 4i, leading to an azimuth amplifier 53 which, in turn, is connected by cable id to the azimuth synchro-transformer and servo-motor represented at 65. These parts will be subsequently described in detail. For the present, it is sufiicient to explain that the azimuth servo-motor is connected, through reduction gearing, to drive the rotatable head of the panoramic telescope carried by the gun for movement in train therewith.

Likewise box 4E has a multi-pole receptacle for a connector 42 extending to an elevation amplifler 46 which is connected by cable 41 to the ca'sing l'8 for the elevation quadrant, synchro-trans 6' former and servo-motor. The box 40, connectors 4i and d2, and amplifiers 43 and 46, are all carried by the gun, while extension junction'boxes 3?, connectors 65, 3 6, unit 33 and main junction box 35, may be mounted upon a power supply unitsuch asa truck or trailer. The connectors 33, 3 9, etc., may have any length up to about 400 yards. By the connections described one director and generator unit may supply data andpower to control four relatively remotely positioned guns.

The on-carriage mounting Figures l and 5 show the invention as applied to a standard 155 mm. gun or howitzer. Referring to Figure 4, the gun is mounted upon a bottom carriage to which a traversing are is secured. A top carriage assembly 5| is mounted upon the bottom carriage, for pivotal movement about a normally vertical axis with which are 533 is concentric. Top carriage assembly 5! includes bearings 52 within which trunnions are held by bearing caps 5c. The trunnion bearings are held in place by plates 53. These caps 54 have integral upward extensions 55 to which the rear ends of respective equilibrators 56 are pivoted at 51'.

The purpose of the equilibrators is to balancethe weight of the gun so that it can be elevated without difficulty.

The gun barrel 5? is mounted for sliding movement in a direction parallel to its bore, upon a cradle and recoil mechanismetil. Said mechanism is, in turn, fixed to andsupp'orted by trunnions 53, Training of the gun is effected by a trainer sitting in seat 58 and turning hand wheels 59 and 86 by means of handles 6| and 62. Turning of these handles effects rotation of a pinion 63,, in mesh with arcuate rack 50, through a mechanical drive shown clearly at Figure 6, and comprising bevelpinions H35, shaft I06, bevel gears Hill, shaft E83, worm Hi9, gear H5, and shaft Hi to which traverse pinion 63 is keyed. This drive is enclosed within housings 6%, 55 and 66, connected by tubular connections '61 and 68, as shown in Figure 4.

The panoramic sight is indicated generally at it and is carried upon a mount T! having a collar 12.journaled upon an inner collar 73 which, in turn, is carried by a support M in alignment the trunnion axis of the gun-and defining an axis that is adaptedto be maintained parallel to the bore of the gun. Cross-leveling mechanism i5 is provided to rotate the mount H about the aforesaid axis to efiect corrections for errors in aim otherwise introduced by tilt of the trunnion axis in the manner well-known in the art. The mount 7! has an upstanding socket 1-6 to receive and support the sight-proper. This sight censists of a vertical tube '1'! received within the socket it, an eye-piece or ocular ll" projecting from tube 77; through 'aslot '18 in socket i5, and an objective or panoramic portion it mounted at the top of tube H 'for rotation through 360 of angular movement 'about'a normally vertical axis. Rotation of objective 'I'S'is effected by a shaft '85 which, in accordance with well known construction, 'carries'a worm in mesh with a gear attached to objective 1B.

A casing 8! is fixedly mounted'upon a bracket 82 carried by the gun trunnion support and, as shown schematically in Figure'6, has a shaft 83 in alignment with shaft 83 and adjustably connected ihereto through a coupling-8'4. By "rotationJof knobs 85 of .this'coupling, relative rota- Casing 8 l "haswindowsiifi and I 85 through which indicator dials 81, 88 and 89, Figure 6, may be observed. The purpose of these dials will be subsequently described. Covers for receptacles for the various electrical connections, are indicated at 90 and 9|. The azimuth servo amplifier 43 is mounted on top carriage 5|. See Figure 4. A milliammeter I63, Figure 6, may be observed through a window 94 at the top of the amplifier. An azimuth indicator is identified at 93. Cable 60 effects electrical connection between amplifier 43 and servo-motor casing 8 I Turning now to the right hand, or elevation side of the gun, an elevation hand wheel 95 (Figure 5) is keyed to a shaft 96' journaled in the top carriage assembly. Reduction gearing is mounted within a casing 96 and has its input geared to shaft 98' and its output keyed to a pinion, not shown, in mesh with elevation are 91. Arc 91 is bolted to the lower surface of cradle assembly 69 and is, of course, concentric of the trunnion axis so that the gun may be elevated or depressed by turning of hand wheel 95 in the direction in which it is desired to rotate the gun. The trails for steadying and stabilizing the gun when in firing position, are identified at 98 and 99.

The elevation quadrant, synchro-transformer and elevation servo 48 are mounted within a case ing carried by top carriage assembly 5|. A level in the form of a bubble tube IOI is carried by a shaft, not shown projecting from casing I00. This shaft is parallel to the trunnion axis of the gun and level I| is normal thereto so that the longitudinal axis of the bubble tube lies in a vertical plane parallel to a vertical plane through the axis of the gun bore. As the elevation servomotor is rotated under the control of signals from the director, level IOI is turned in the aforesaid vertical plane at a rate equal and opposite to the rate of gun elevation necessary to keep the gun continuously correctly elevated. The operator then turns hand wheel 95 to maintain the bubble of level IIlI centered, and in so doing continuously maintains the gun at the elevation computed by the director.

A micrometer scale and actuating knob are identified at I03 for hand operation of level when desired or when the director is out of operation. Numeral I04 indicates the removable cover for a ready signal lamp. The elevation amplifier 46 is fixed to the top carriage 5| and is electrically connected with the elevation quadrant 48 by cable 41, as described in connection with Figure 3.

The azimuth sight control Referring now to Figure 6, dotted line I4a. indicates the azimuth portion of director I4. This director may be a standard instrument such as the Armys M8N or MBP. It is suffici-ent to explain, therefore, that the final predicted azimuth output of the director results in the rotation of the rotor I I2 of a coarse transmitter I I3 and the proportional rotation of rotor I I4 of a fine transmitter II5. These transmitters are conventional Selsyns or Autosyns. The rotors are mechanically connected in a 36:1 ratio such that II4 makes 36 rotations for each rotation of H2. Graduated dials H6 and H1 are connected to the respective rotors to indicate the rotations thereof. Rotors H2 and H4 as well as all others subsequently described, are supplied over conductors 34 with standard 115 volt, 60 cycle A. C. current from unit 33. Transmitter |I3 has field coils II8 Y-connected over the cables in :connectors 3|, 35, 38, 4| and 44,Figure 3, to the field coils I2I of coarse repeater I20, having a rotor winding I22 mounted upon a shaft I23. Dial 89' is secured to this shaft. Similarly, the field coils I I9 of transmitter I I5 are Y-connected to the field coils I of fine repeater I24. The rotor I26 of repeater I24 is connected to shaft 03, previously mentioned.

In an ordinary Selsyn hook-up, rotation of rotor M4, for example, would cause a like rotation of the field induced in field coils H9. This field rotation would be repeated by receiver coils I25 to thereby effect a rotation of repeater rotor I26 until the field thereof is parallel to the new position of the resultant field of coils I25.

In my invention, the repeater rotors I22 and I26 are rotated in synchronism with their respective transmitter rotors H2 and H4, b a motor I21 having one phase I28 continuously energized from source 33, by way of connections subsequently traced, and a second phase I29 adapted to be energized by and upon rotation of the resultant field of field coils I25, relatively to rotor I25. Motor I21 therefore rotates only during such times as its phase I29 is energized; and its rotation ceases as soon as rotor I26 is aligned with the new position of the field of coils I25. The manner in which precise energization of phase I29 is effected will be subsequently described in connection with Figure 7. Rotation of rotor I30 of motor I21 drives shaft 83 and fine repeater rotor I26, through a 250:1 reduction gear train indicated generally by the numeral I3 I. At 2400 R. P. M. for motor I21, a maximum tracking rate of 1.6/sec. is provided.

The final drive of train I3I is a gear I32 fixed to shaft 83. This shaft also has fixed thereon, a pinion I33 and a gear I34. Gear I34 meshes with a gear I35 on shaft I36. Fine indicator dial 88 is fixed to shaft I36. Since I34 and I35 are of equal diameter, while shaft 83 rotates 36 times for each 360 rotation of telescope head or objective 19, dial 88 rotates once for each 10 rotation of the line of sight. A 36:1 reduction gearing is indicated at I31, between fine dial 88 and The azimuth and elevation synchronizers The two synchronizers are essentially alike and differ only in the gear ratios by which they are connected to the respective fine repeaters. Hence a description of the azimuth synchronizer, as illustrated in Figures 6, 7 and 8, will suffice.

It has previously been explained that the fine azimuth repeater shaft 83 rotates 36 times for each 360 rotation of telescope head. This reduced ratio provides a high degree of accuracy but, standing alone, might introduce ambiguity because of 36 possible positions in which shaft 83 and rotor I26 would be in step with transmitter I I4. The coarse transmitter I I3 and its repeater I20 are provided to avoid this ambiguity.

As previously stated, rotors H4 and I I2 in the director, are connected in 36:1 relation by mechanism not shown. Likewise shaft 83 is connected with shaft 200 of the synchronizer by a 1:36 reducing connection that includes pinion I33 meshing with gear 20I fixed with pinion 203 \on countershaft 202. Pinion 203 meshes with a gear The sleeve also has a radially and axially-extend,

aweeee ing arm 299 on which are mounted a pair of contacts 2H1 and 2H spaced ina plane normal to, and circumferentially of, the axis of shaft 261) and shaft I23 coaxial with shaft 290. A suitable bearing support, not shown, is provided for the end of shaft 523, remote from repeater I20. Rotor I22 of coarse azimuth receiver I23, is connected with shaft I23. A contact element ZIS is journaled in a bearing 2| 4, coaxially of shafts 290 and !23. This element comprises a disc having an internal heart-shaped cam 22 I and a projection 218 having contacts 2i? and 288 interposed between and adapted to engage contacts 2H! and 2! I, for respectively opposite directions of relative rotation between element 2I3 and shaft 20s. The proportions are such that a rotation of element 2I3 about 3 in either direction relatively to shaft 2M, results in the closure of a respective pair of contacts.

A yielding, self-centralizing connection is. afforded between shaft I23 and element 2H3 by the cam 2E5, in conjunction with a roller 2H9 urged radially outwardly into contact with the cam surface by a spring 220. This yielding connection has been omitted upon Figure 6 to avoid confusion. Conductors 22! and 222 lead from contacts ZIii and 2|! to slip rings 205 and 298, respectively, while a third conductor Z23 connects both contacts 2!! and 2 IS with slip ring 201. By the foregoing construction, contact is made at 2 I i! or 2!! whenever shaft l23, under the control of coarse repeater I26, rotates relatively to shaft 200, by a minimum of 3 in either direction. Thus shaft 289 rotates in 1:1 ratio with telescope head or objective E9. The contacts 2m and 2 act to control the amplifier i3 and, hence, motor Q21, through connections that Will be subsequently traced. Since contact is made at ZIEJ or 2 Whenever the coarse repeater is out of step by a minmum of 3, any ambiguity that might otherwise be present in the position of shaft 83, is avoided and said shaft is kept within the sector necessary to accurately reproduce the predicted. azimuth of the director. The elevation synchronizer is identified by the numerals 291 to 3%, inclusive, Figure 6A, and in view of the fact that it is identical in construction and operation with the azimuth synchronizer, it is deemed unnecessary to describe it in detail.

The azimuth indicator Occasions arise in combat where it is necessary to position the guns in azimuth without the use of the azimuth telescope. For use in such situations I have provided an azimuth indicator shown schematically in Figure 6, where it will be noted that a repeater or synchronous transformer H38, has field coils I39 Y-connected over cable MI, with the corresponding coils of transmitter H5. lhe rotor I48 of repeater :38 is mounted upon a shaft I52 having thereon a gear I43 and a fine dial I44. A 36 to 1 reduction gearing, indicated at MS, is interposed between fine dial i 5 and a coarse dial 545. Since the field of coils rotates in synchronism with that of fine transmitter H5, rotation of rotor Mil to maintain its coil in alignment with the resultant field of coils I39 will result in synchronous rotation of dials M6 and M5 with those of dials 88 and 8?. respectively.

Gear 5 53 is connected to one side l liav of a differential It! having its center connected to a shaft 55%] connected with gear Iii), and hence, with shaft I! I and traversing pinion 63,.

The

gear ratios are such that the gun is traversed or trained through 10 for each rotation of dial Hi4 and in 1:1 ratio with dial M5. The second side I i-9 of the diiferential is adapted to be operated by a knob I5! through a connection including shaft l52, reduction gears E53, shaft I54 and reduction gears l 5 and IE5. The overall reduction ratio may be 1:12 so that fine knob IE5 is rotated twelve times for each rotation of gear I56. Gear I56 is mounted upon a shaft I5! to which a coarse knob I58 is attached whereby the angular adjustments effected by knob IEI may be determined. Shaft I52 is normally locked against rotation by a releasable detent I59 of any suitable construction.

Rotor MI] is connected by conductors I60, with a phase detecting circuit It having an output S62 connected to control an error meter or milliammeter I63. The connections are such that when director rotor H4 is rotated through a certain angle, the field induced by coils I39 is correspondingly rotated and moved from its previous position of alignment with the electrical axis of rotor Me. As a result of this lack of alignment, an alternating potential is induced in rotor I40 whose phase depends upon the direction of rotation of rotor H4. This potential is then detected as to phase in circuit I6! and the output applied to meter it to deflect indicator 512 in one direction or the other, depending upon the direction of rotation of rotor I I4. Thus any deflection of indicator ltd informs the trainer that the gun is not at the proper azimuth angle predicted by the director, and he may bring about agreement by operating his hand wheels 59 and to until pointer its is returned to null or zero position. The connections are such that a deflection of its to the right requires a training movement of the gun to the right.

Circuit ISI is mounted within amplifier housing 53, Figure 4, and meter I63 is positioned to be viewed through window at. In normal operation, the trainer observes the aiming point 25 through sight it? and effects the training movement indicated thereby. Should the point 29 become obscured, he has only to shift his eye to meter I53 and continue training in accordance with the indications thereof. The use of meter M53, is essentially less accurate than sighting on aiming point 29 since its accuracy depends upon the stability of the gun carriage and does not correct for azimuth errors introduced by shifting of the It does, however, provide a means for effecting satisfactory training under more or less emergency conditions.

The drive to side M9 of differential It? from knob I5! is normally locked by detent I59 so that the drive from hand wheels 59 and E0 to rotor I40, proceeds directly through the differential. When the trails 9i} and 59 of the gun are shifted to cover a diiferent sector of fire, a new horizontal base or reference line is, in efiect, established. Thus, after the gun and director are adjusted with their base or reference lines in parallelism, hand 564 will ordinarily not be centered. centralization can then be effected by releasing detent I59 and turning knob I58 until substantial centralization of hand 55% is produced. Exact, centralization can then be effected by adjustment through line knob 55L after which shaft IE2 is again locked by detent I59. After this adjustment the meter 553 may be used for control of the azimuthal position of the gun in the new sector.

The elevation quadrant control Referring more particularly to Figure 6A, the elevation portion of the director is indicated by the dotted lines I41) and includes a fine transmitter I65 having a rotor I66 and field coils I31, together with an indicator dial I88 connected for rotation with rotor I66. A coarse elevation transmitter is indicated at I69 and includes a rotor I18, field coils I1 I and an indicator 112 connected for rotation with the rotor I18. Both rotors I66 and I19 are supplied with alternating potential from source 33.

The fine elevation receiver is indicated at I15 and includes rotor I13 and field coils 514, Y- connected with transmitter coils I31 in the conventional manner. The coarse repeater 116 in cludes a rotor I11 and field coils I18. The rotor of fine repeater I15, is connected for rotation with a shaft I19. An adjustable coupling I853 connects shaft I19 to a shaft I8I which, in turn, drives elevation quadrant 48 through gearing I82. Access to this coupling may be had by removing cap 295, Figure 5. It may be adjusted to effect relative rotation between shafts I19 and I8I, or to entirely disconnect said shafts.

When disconnected, data may be introduced manually into the quadrant.

A two-phase motor I83 has one phase I84 continuously energized and a second phase I36 connected for energization under the control of amplifier 46 whenever the field of rotor I13 and the resultant field of coils I15 are out of parallelism so that a potential is induced in the coils of rotor I13. Motor I 83 drives shaft I19 through a reduction gear train I88 having a final gear I89 fixed which a coarse elevation indicator drum I96 is driven. In the installation disclosed, these drums are located at the lower left of quadrant 48, as viewed in Figure 5. The over-all gear ratios are such that the elevation quadrant rotates 100 mils 1 per revolution of drum I94 and 1600 mils per revolution of drum I96.

Director rotors I66 and I18 are connected by mechanism not shown, for rotation in 16:1 relation. When rotor I66 is moved by the director mechanism in accordance with predicted values 5 of gun elevation, the resulting rotation of field induced in coils I61 is repeated by coils I14. The resultant field of coils I14 now induces a potential in rotor I13 which is amplified in amplifier 46 and applied to phase I 86 of motor I83 which now turns at high speed to drive shaft I19 and rotor I 13 until the latter is in its previous relation with the field of coils I14. When this relation is restored, no potential is induced in the coils of rotor I13 phase I86 is de-energized and rotation of motor I83 ceases.

The amplifiers Closure of the azimuth synchronizer circuits through contacts 2I8 or 2 I I, results in the application of a relatively large voltage to the input of the amplifier. The phase of the voltage thus applied varies according to whether contact is made at 2I9 or 2I I. Referring to Figures 6 and 7, 225 and 226 represent input cOnduGtQ I 9 nected to generator unit 33 shown at Figure 6, and supplying the primary 228 of transformer 221 having secondary windings including 229 and 238. Either of windings 229 and 236 is adapted to supply the primary 232 of synchronizer transformer 23! depending upon whether contact is closed at 2I6 or 2.

Normally, that is, with contacts 2I9 and 2H open, primary 232 of amplifier transformer 23I, is supplied from fine transmitter rotor I26 over conductors 234 and 235, the former having therein a resistor 242 of 1 K. and 10 watts power capacity. Should the relative rotation between shafts I23 and 299 exceed 3 in one direction, contact is made in the synchronizer at 2!!) and the circuit then proceeds by conductor 22I transformer secondary 229, conductor 233, primary 232, and return line 223 to the synchronizer. In case contact is made at 2II the circuit proceeds by way of conductor 222, transformer secondary 23!], conductor 233, primary 232,and return 223, to the synchronizer.

In both cases, a signal of approximately 20 volts is applied to primary 232. This voltage while modulated by the voltage induced in rotor I26, is sufficiently large so that an error signal will always be applied to primary 232 irrespective of whether or not the signal from rotor I23 is in or out of phase with the signal from transformer 221.

The secondary 236 of transformer 23I is connected over lines 231 and 238 to the grids of a dual triode 239, which may be a 6SL'1 or similar type of tube. Connection is made through capacitors 248 and 24I of 0.03 mi. each. The plates of tube 239 are connected with the primary 243 of a transformer 244, through a fixed resistor 245 having a value of 10 K. and a variable resistor 246 having a maximum value of 20 The center tap of primary 243 is grounded through a capacitor 292 of 0.25 mi. and a resistor 283 of 25 K. Resistor 243 is made variable because it is difficult to find a dual triode tube whose electrical characteristics are identical in both sections. Any difference between the two sec tions, as well as other possible unsymmetrical circuit constants, can be balanced out by adjustment of this resistor until the voltage drop across the mid-point of winding 243 and the two plate terminals, are equal. A 350-volt winding 259 of transformer 221, supplies plate voltage for tube 239 over connections that will subsequently be traced and that include a resistor 25I of 20 K. connected in line 252 leading from one terminal of winding 258 to the common cathode terminal 253 of tube 239. Resistor 2-5I provides a voltage drop giving an additional component of grid bias to thus afford wide pulses of plate current without grid current. A capacitor 241 of 0.02 mi. is connected between the plate terminals.

Now consider a condition in which there is no error signal applied to winding 232 During that half of the cycle when the plates of tube 239 are positive with respect to the cathodes equal plate currents will flow in the tube sections and the resulting voltage drops across the two halves of the transformer winding 243 will be equal at each instant so that the net drop across the winding will be zero and no current will flow.v Consider that an error signal is applied to primary Winding 232 of transformer 23I, through.

closure of contacts in the synchronizer and thatthe phase of this error signal is such that theinduced voltage in the left half of secondary- 236, as viewed in Figure '1, is in phase with the:

13 plate voltage. That-is, when the grid voltage is positive, the plate voltage is: also positive. The positive grid voltage causes a large plate current to flow in the corresponding section of tube 239 which results in a large voltage drop across the corresponding half of primary 243. Since, under the same conditions, the right hand terminal of secondary 235 is negative, the resulting voltage applied to the grid of the other half of tube 239 results in a reduced plate current therein with a consequent reduced voltage drop across the other half of primary 2 33 and the net voltage across said primary is equal to the difference between the voltages applied to the two halves. The voltage drop across the left half of winding 253, being greater than that across the right half, terminal 253 is more negative with respect to ground than terminal 254 and the resultant voltage between terminals 253 and 1 will be in phase opposition to that across the terminals of secondary 236.

Again, consider the effect when the phase of the error signal applied to primary 23-2 is reversed from that assumed in the preceding paragraph. In this case, the left terminal of secondary 236 and its grid of tube 238, are negative when the plates of the tube are positive so that a reduced current flows in the corresponding tube section. Since the grid of the right half of tube 239 will now be positive when its plate is positive, a large plate current will flow in this half of the tube and the voltage drop across the corresponding section of transformer winding 223 will be greater than that across the other or left half. Terminal 254 is now more negative with respect to ground than 253 and the resulting voltagebetween 253 and 254 Will be in phase with that across the terminals of secondary 236. A capacitor 249 of 0.02 mf. is connected across the grid terminals to tune the circuit to 60 cycles and thereby reduce harmonics of 60 cycles in the error signal supplied to the grids which harmonics would cause one of the tube sections to have a much lower gain than the other. Thus a voltage appears between terminals 253 and 254 whenever an error signal is applied to winding 232 of transformer 23!. This voltage has a polarity dependent upon whether contact is made at 2I0 or 2| I. While the description has been, and will be made with respect to the relatively large voltage applied to transformer primary 232 upon closure of contacts in the synchronizer, it will be understood that the same effects are produced when the field induced in coils I25 rotates relatively to rotor I26 and thus induces a potential in the primary 232. Any difference is one of degree only.

As has been previously stated, phase I28 of two-phase motor I21 is continuously energized from winding 229 of transformer 221, over conductors 255 and 256 as will be obvious from in-- spection of Figure 7. In order that rotation of motor I21 may be ei fected and in the proper direction, the phase of the voltage in I 29 must be caused to lag or lead the phase of the voltage applied to I28, by 90. This phase shifting is effected by connections wherein terminals 253 and 254 of transformer winding 243, are connected to the control grids of a pair of beam power amplifier tubes 251 and 258 such as the (W6, over conductors 258 and 250 having resistors 2EI and 262 of 2M9 each, and capacitors 253 and 254 of 0.03 mi. each, Capacitors 265 and 266 of 0.01 mg. each are cross-connected between conductors 259 and 260, as shown to provide the necessary phase shift: with a minimum of attenuation. Thev grid bias; for tubes 25.! and 25B is provided by the drop across a resistor 261 having values. of 2500 and 10 watts. A resistor 26.8 of 1 K, and 2 watts, is connected as shown between the screen grids of tubes 251 and 25.8, and. the plate supply voltage. from a secondary winding; 25.2 of transformer 221, and acts to drop the plate voltage to a value suitable for the screen grids. Capacitors 210.- and 2H of 0.02 mi. are connected as shown between output transformer 21.2 and ground to make it resonant at cycles and reduced harmonics in the output.

The plate voltage supply for the output stage is obtained by a full; wave rectifier tube 213 such as a. EYS-G with condenser-input filter 214' of 3 mi. and connected to. 350-vo'1t winding 250 in a manner obvious from inspection of Figure '7. The center tap of secondary winding 236 is conheated by conductor 215 to a common terminal of voltage dividers. 216. and 211 of 50 K. and 1'70 K., respectively, to provide an additional component of A. C. grid bias voltage and aid in effecting wide pulses. of plate current in tube 239 without grid current. This A. C. bias swings the grids in the positive direction with respect to the cathodes during the time that the plates are positive with respect to the cathodes. Because of the combined effect of the degenerative action of the cathode resistor 25I and the aforesaid A. C. bias, the plate current is held fairly constant during the time that the plates are positive with respect to the cathode, and plate current is provided in relatively wide pulses so that motor I21 may develop maximum torque for a given average plate current. Heater filament current is supplied from winding 218 of transformer 221.

Regeneration is effected to increase the plate currents in tube-239' by connecting the plate of one section through series-connected resistors 219 and 280 of 5M9 and 1.5Mn, respectively, to the grid of the other section. Likewise, the plate of the second section. is connected through seriesconnected resistors 28I and 282 of 5M0 and 1.5MQ, respectively. A twin diode 283, such as 6H6 or 6216GT, has its plates connected to the ter minals of the secondary 228 of transformer 22:? In order to prevent hunting, secondary 228 is so wound that the voltages at terminals 253 and 282 are in phase as are those at terminals 254 and 285. Cross connections between the plates of tube 239 and the cathodes of diode 283, are completed through capacitors 286 and 281 of 0.05 mi. each.

The preceding description has been made in connection with azimuth amplifier t3. It will be understood that elevation amplifier 46 is essentially the :same in construction and operation. However, in the azimuth amplifier, the gear ratio between motor I21 and shaft 83, is 250:1 while in the elevation. amplifier, the corresponding ratio is about 130021. This difference in ratios makes the azimuth section of the system more rapid in action than the elevation section and, as a result the time constant of the anti-hunting circuit in the azimuth section must be of less duration than that in the elevation section. To provide this time difference, additional resistors 2338 and 289 of 5M9, are placed in series with resistors 280 and 282, respectively when the amplifier is used for elevation control, and are shorted out by contact blades 29.0 and 29!, when the amplifier is to be used for azimuth control.

The operation of the regenerative circuit will be obvious to those skilled inthe art and. may be briefly described as follows. Assume that the error signal voltage at the terminals of secondary 236 is in phase with the plate supply voltage, that is, that the grid of the left section of triode 239 is being swung more positive with respect to its cathode. Under this condition, terminal 253 is more negative with respect to ground than if no error signal were being applied to transformer 23I. At this instant the grid of the right hand triode section is being swung more negative with respect to the cathode. The additional negative voltage component from the plate of the left triode section will be added to the error signal through resistors 28 I 282 (when used), to the grid of the right section to drive it still more negative with respect to its cathode and further reduce the plate current in said section. The reduction in plate current will reduce the voltage drop between terminal 25% and ground and cause the terminal to become more positive with respect to ground. As a result, the normal negative component fed from the plate of the right section of tube 239 is further reduced. The grid of the left section is therefore made more positive with respect to the ground thereby acting to reinforce the error signal and causing the plate current to increase still further.

Thus the voltage drop across primary 243 is much greater than with straight amplification. Because of the symmetry of the circuit, similar regeneration will occur when the phase of the error signal is shifted 180. Resistance and capacitance in the circuit act to delay regeneration slightly.

As an example of how the foregoing regeneration adds to the accuracy and sensitiveness of the system, suppose that repeater shaft 83 is displaced from its zero-error position, that is, alignment of the electrical axis of rotor I26 with the resultant field of coils I25. If simple non-regenerative amplification alone were employed the amplifier could cause the motor I21 to drive the shaft 83 toward zero-error position but the torque developed by the motor would decrease with the resulting decrease in the error signal. Since friction in the mechanical part is unavoidable, the motor would come to a stop when its developed torque becomes equal to the resistance due to friction, thus leaving a considerable error lag of shaft 83 form true no-error position.

The regenerative feature prevents such errors. If a small error signal persists for a period of time, the regenerative feed-back circuit causes the motor torque to build up, relatively slowly, to full or maximum value. This function is effected, no matter how small the error signal and the only effect of the amplitude of the error signal is to determine the rate at which the motor torque builds up. That is, any persistent error signal, no matter how small, causes the regenerative feed-back to develop a torque in motor I21 that increases as long as any error persists. In all cases, this torque becomes large enough to overcome friction and to drive the shaft 83 to its true zero-error position.

Under some conditions the voltage built up by regeneration may continue after shaft 83 has reached zero-error position as determined by repeater I24 and thus cause the shaft to overshoot. As soon as the overshooting begins, however, the regenerative circuit receives a voltage of opposite phase which reduces the output of the amplifier so that simple amplification of the error signal develops a countertorque. As a result, the shaft 83 is moved to zero-error position, in spite of friction, with not more than one overshoot, and usually aperiodically.-

Operation In operation of the system, the gun and its director, generator unit and any other auxiliaries, are placed in the positions selected by the battery commander and interconnected by multi-conduit cable. The director is adjusted in the conventional manner so that the elevation signals transmitted to the gun are with reference to a horizontal plane. A reference stake is set at a point easily visible through panoramic sight 'IEI and the director is adjusted so that its azimuth output signals are with reference to the projection upon a horizontal plane, of the line between the pivot center of the gun, that is, the intersection of its train and trunnion axes, and the aforesaid aiming stake or a horizontal line making a known angle with such projection. The telescope mount is longitudinally leveled and cross-leveled, and head I9 of telescope I0 is rotated in azimuth until the vertical cross hair in its line of sight intersects the aiming stake. The head may be turned in elevation by its elevation adjustment if this is necessary to bring the stake into the field of view. The coarse and fine indicator dials 81 and 88 are adjusted independently of the shaft 83 by a releasable coupling, not shown, to read the same as the corresponding dials of the director and again coupled to the shaft. Knob I5I is turned until the indicator I64 is centered. The knob is then looked. The director is then electrically coupled to the respective repeaters at the gun, by the closure of appropriate switches.

Assuming that the members of the crew are at their stations and that a target to be engaged is sighted or otherwise identified and designated by the battery commander, the director is trained upon the selected target and begins to deliver azimuth output signals which appear at the gun as proportionate rotations of the fields of coarse and fine repeater coils I2I and I25. Assuming that motor I2! is at rest, with only phase I28 energized, as soon as rotation of the field of coils I25 takes place relatively to rotor I26, a potential is induced in the latter having a phase dependent upon the direction in which the relative rotation has taken place. This potential is applied over conductors 234 and 235 to primary 232 of transformer 23I and, after amplification and phase shift, as explained in connection with the description of the amplifier, acts to energize phase I29 of motor I2'I, to cause a rotation of the motor I21 and shaft 83, in the direction necessary to restore alignment between the electrical axis of rotor I26 and the field of its coils I25. It has been explained that shaft 83 is geared to rotate 36 times for each 360 rotation of the objective I9. Since the rotors of transmitters H3 and H5 are geared in 1:36 ratio in the director, repeater I20 prevents ambiguity by rotating shaft I23 in step with the rotations of rotor H2 and effecting closure of one or the other of contacts 2I0 or 2 when relative displacement of about 3 occurs between shafts I23 and 200. Thus shaft 83 is rotated in step with rotor II I without the possibility of ambiguity.

At the start of the encounter, the trainer, in seat 58, looks into eyepiece TI and, by operation of hand wheels 59 and 68, turns the gun and sight as a unit about the vertical or train axis, until the vertical cross wire of his telescope, appears to intersect the aiming point or reference stake. The motor I 21, under control of the director azimuth signals, rotates objective l relatively to the gun, equally and oppositely to the rate at which the gun should be moved in azimuth to continuously engage the target and, as the trainer, through operation of his hand wheels maintains the telescope cross hairs upon the target by moving the gun and sight as a unit, the gun is continuously properly aimed in azimuth in accordance with the predicted values of the director. Train rates of .005 to 1.5" per second are possible in the installation selected for illustration.

Should the aiming point 25! be destroyed or obscured by smoke or fog, the trainer simply shifts his glance to meter I63 and continues to operate hand wheels 59 and 56 in the manner necessary to keep indicator use centered or at null reading. Two or more aiming points may be provided and shift from one to another may be made by disconnecting coupling 84 and rotating head "50 to direct the line of sight to the new point. The coupling is then closed and aim ing maybe resumed in the usual manner.

Simultaneously with the training operation just described, predicted elevation. values are received at the elevation amplifier 48 from coarse and fine elevation. transmitters I69 and IE at the director. Relative rotation between rotor I '13 and the field of coils I'M energizes the phase I86 of motor m3 and causes the motor to rotate and to drive shaft 1'59 and quadrant 48. Synchronization is effected in the manner described in connection with the azimuth amplifier so that motor 115 is at all times in step with transmitter I65 and level lfll is smoothly and continuously pivoted relatively to the gun about an axis parallel to the trunnion axis in accordance with the director output elevation rate and in a direction opposite to the required elevation or depression of the gun about its trunnion axis.

Theoretically it is then merely necessary for the pointer to operate his hand wheel 55 to elevate the gun and quadrant as a unit, to keep the bubble of level iii! centralized, in order that the gun may ,be continuously properly elevated. This procedure is contemplated with certain types of guns and mounts and is within the pur- View of my invention. However, the 155 mm. unit disclosed, is equipped with a hand-operated brake which must be set before firing and which of course, precludes elevation of the gun as long as the brake is set. In actual firing of the unit disclosed, therefore, the pointer, shortly before the gun is ready for firing, advances the gun ahead of the proper instantaneous elevation by 3 or 4 mils. This is done by elevating or depressing. the gun as the situation requires, until the bubble tube is off center by an amount corresponding to the desired advance, namely, 3 or 4 mils. The pointer then sets the brake by operation oflever 2%, Figure 5, and continues to watch the bubble of level as it approaches nearer and nearer to centralized position under the drive from motor 183. At the instant that the bubble is centralized, the pointer calls set or makes an equivalent signal. The gun is fired at this instant. lhe pointer then releases the brake, advances the gun and level by another 3 or 4 mils, and again awaits centralization of the bubble. In the unit selected for illustration, elevation rates of from .05 to 3 mils per second are available. I

The casing 58 is provided with a conventional cross-leveling mechanism and level adjusted by a knob 296, Figure 5. During firing, the trainer 18 and pointer occasionally glance at their respective cross-levels and efiect any adjustments of cross-leveling knobs l5 and 296, necessary to centralize the respective levels. it will be understood that conventional means are provided for adjusting or rotating each of the repeaters with respect to its transmitter at the director and for securing it in adjusted position so that, in all cases, the receiver dials may be adjusted to agree with the corresponding dials of the director.

This may be done, for example, by mounting each repeater so that it may be adjusted bodily about its rotor axis and then locked in position. The coarse dial 89 is provided so that the fine repeater 53-3 may be oriented when the remainder of the azimuth receiver servo fails to function.

There is thus provided a gun aiming system that is rapid in action, and highly accurate and flexible in operation. Each unit may include from one to four guns and, during an engagement, the rate of fire of each gun is limited only by the time necessary for loading and firing.

'As a result, the maximum concentration of accurate fire from each battery equipped with the invention is assured.

While I have disclosed a preferred form of the invention as now known to me, numerous modificati'ons and substitutions of equivalents will readily occur to those skilled in the art of gun fire control without alteration of the basic principles upon which my invention operates. The foregoing disclosure is therefore to be taken in an illustrative, rather than a limiting sense; and it is my desire and intention to reserve all such changes, modifications and substitutions as fall within the scope of the subjoined claims.

Having now fully disclosed the invention, what I claim and desire to secure by Letters Patent is:

1. The combination with a gun and sight trainable as a unit about a first axis, said sight being mounted for pivotal movement through substantially 360 of angular movement relatively to said gun about a second axis parallel to said first axis, of a remote director, telemetric power means connecting said director and sight, said telemetric means acting under control of said director to rotate said sight relatively to said gun.

2'. In a gun aiming system, a gun mounted for training about a first normally vertical axis, manually operable means connected to so train said gun, a sighting device carried by said gun for training therewith, said sight having an objective rotatable relatively to the gun through substantially 360 of angular movement about a second axis parallel to said first axis, to angularly move the line of sight thereof relatively to said gun, a remote director having an output proportional to the angularmovementof a remote target, and electric power means rotating said objective by and in response to said director output.

3. In a system for aiming a gun mounted for elevation on a trainablecarriage, a sight on said carriage having a portion adjustable to shift the line of sight thereof in azimuth independently of said carriage, a level carried by said gun and disposed parallel to a vertical plane through the axis of the bore of the gun for pivotal adjustment about an axis parallel to the elevation axis of the gun, first and second servo-motors connected to adjust said portion and said level, respectively, andc'ircuitme'ans adapted to control said servo motors by and in accordance with the predicted gun azimuth and elevation outputs of a remote director.

4. In a gun aiming system, a gun trainable about a first normally vertical axis, a sight carried by said gun for training therewith, said sight having an optical obj ective'rotatable relatively to said gun about a second axis parallel to said first axis and effective on rotation to correspondingly angularly rotate the line of sight thereof to a distant aiming point, a remote director having an output proportional to the future predicted azimuthal position of a target to be fired upon, an electric telemetric connection between said director and objective automatically rotating said objective relatively to said gun, by and in proportion to the movement of said output, in a direction opposite to the apparent motion of said target, and manually operable means effective to rotate said gun and sight as a unit, to maintain said line of sight upon an aiming point other than said target.

5. In a system for continuously aiming a gun mounted for training about a normally vertical axis, and having manually operable means to effect said training, a sight on said gun and movable therewith in train only, said sight being adjustable, to rotate in azimuth relatively to said gun the normally horizontal line of sight determined by said sight, a servo-motor carried by said gun and connected to so adjust said sight. 9

means on said gun to automatically operate said servo-motor in accordance with signals received from a remote director and thereby move said sight to continuously rotate its line of sight equally and oppositely to the movement in train of said gun necessary to continuously engage a moving target, whereby said gun is continuously properly trained by an observer looking through said sight and operating said manually operable means to maintain said line of sight upon a pre- 7 selected fixed aiming point.

6. A system for aiming a gun to continuously engage a moving target, said gun having manually operable training mechanism, a sight connected for movement in train with said gun and having a part adjustable to rotate its line of sight relatively to said gun in azimuth, a motor connected to so adjust said part, means to operate said motor in accordance with signals generated by a remote director to thereby continuously move said line of sight at a rate equal and op-- posite to the rate of azimuthal gun rotation necessary to continuously engage said target, whereby, an operator may continuously correctly train said gun by operating said training mechanism to rotate said gun and sight as a unit to maintain the line of sight thereof on a pre-se- .lected fixed aiming point remote from said gun.

'7. In combination with a gun having means to elevate the same about a normally horizontal trunnion axis, an elevation quadrant mounted on said gun and having a part pivoted for movement about an axis parallel to said trunnion axis, a level indicator carried by said part, servomotor means connected to so pivot said part, a remote director, and telemetric connections between said director and servo-motor means, to rotate said part and indicator at a rate equal and opposite to the rate of gun elevation necessary to continuously correctly aim said gun at a moving target.

8. In a system for aiming guns to continuously engage a moving target, a gun mounted for movement about respective vertical and horizontal, train and elevation axes, a sight carried by said gun for movement therewith about said train axis only, said sight establishing a normally horizontal line of sight and being independently rotatable relatively to said gun about a normally vertical axis, a motor connected to so rotate said sight, an elevation quadrant carried by said gun for elevation therewith and including level indicating means rotatable about an axis parallel to said elevation axis independently of said gun, and a motor connected to so rotate said level indicating means, both said motors being adapted for automatic operation under the control of a remote director in accordance with azimuth and elevation angles respectively predicted thereby.

9. An aiming system for a gun having training mechanism and elevating mechanism for moving the gun about respectively vertical and horizontal axes, a sight mounted for movement with said gun in train only and operable to move its line of sight in azimuth independently of said gun, a servo-motor, a synchronous repeater adapted to be controlled by the synchronous transmitter of a remote director in accordance with the predicted azimuth output rate to maintain said gun in azimuthal position to hit a moving target, an amplifier connected to control said servo-motor, and driving connections from said servo-motor, first, to said sight to move the line of sight thereof in azimuth independently of said gun and, secondly, to said synchronous repeater to effect relative rotation of the rotor and stator thereof said amplifier being responsive to departure from predetermined angular relation of the rotor and induced field of said repeater,

whereby said servo-motor is energized to rotate the line of sight of said sight in accordance with the predicted azimuth rate of said director.

10. In an aiming system for a gun having a mount including training and elevating mechanism for moving the gun about respectively vertical and horizontal axes, a sight mounted for movement with said gun in train only, and operable to move its line of sight in azimuth independent of said gun, a first two-phase motor connected to so operate said sight, an elevation quadrant movable with said gun in elevation and train and having a level indicator movable about an axis parallel to said elevation axis independently of said gun, a second two-phase motor connected to so move said level indicator, first and second repeater motors carried by said gun mount and adapted to be controlled by a remote director, first and second amplifiers each electrically connected to control one phase of a respective motor, circuit connections between each repeater motor and a respective amplifier to energize said phase by and upon departure from a predetermined angular relation of the rotor and field of said repeater motor, the remaining phase of said two-phase motors being continuously energized, and a driving connection between each two-phase motor and the rotor of a respective one of said repeater motors.

11. In a system for aiming, by means of a remote director, a gun mounted upon a carriage trainable about a normally vertical axis, a repeater on said carriage and having field coils adapted to repeat the field rotation of a transmitter at said director, said repeater also having a rotor, a sight mounted on said carriage and having a part operable to rotate its line of sight in azimuth independently of said gun, a servomotor, means mechanically connecting said servomotor to rotate said rotor and part,

an amplifier having an output connected to control rotation of said servomotor and an input responsive to departure from predetermined angular relation of said rotor and the resultant field of said field coils whereby said line of sight is rotated in accordance with the rotation of said resultant field.

12. A system for aiming a gun by means of data computed by a remote director, said gun being mounted for elevation upon a trainable carriage, a telescope on said carriage having a part operable to rotate in azimuth the line of sight of said telescope independently of said gun, coarse and fine repeaters on said carriage, each having a rotor and coils adapted to repeat the field rotations of respective coarse and fine transmitters at said director, a motor mechanically connected to simultaneously rotate said telescope part and the rotor of said fine repeater,

amplifier means connected to control rotation a chronizer means including relatively rotatable first and second elements and circuit connections to assume control of said amplifier in response to relative rotation of said elements, said first element being mechanically connected for operation by said motor and said second element being connected for operation by the rotor of said coarse repeater, the connections being such that the rotor of said fine repeater turns a predetermined number of rotations for each rotation of said first element.

13. In a system for aiming a gun mounted upon a carriage having manually operable means for training said un and carriage about a normally vertical a sight on said carriage and having a part operable to rotate the normally horizontal line of sight independently of said gun, first and second repeaters on said carriage each having a rotor and field coils adapted to repeat the field rotations of a single transmitter at a director remote from said gun, a servomotor mechanically connected to so operate said part and the rotor of said first repeater, a mechanical connection between said manually operable means and the rotor of said second repeater, a train indicator, said indicator comprising an ammeter connected for response to relative rotation of the rotor and induced field of said second repeater, whereby said manually operable means may be actuated to correctly train said gun, either by keeping said line of sight directed upon a remote fixed aiming point or to maintain said ammeter in predetermined indicating position, and means responsive to rotation out of a predetermined inductive relation, of the rotor and stator of said first repeater, to effect rotation of said servomotor.

14. A system for aiming a gun from data computed in a director, the gun being mounted for elevation upon a trainable carriage, a synchronous repeater on said gun having a field and a rotor, an elevation quadrant on said gun including a bubble tube level, said quadrant and level being pivoted for movement independently of said gun about an axis parallel to the elevation axis of said gun and adapted to indicate a level position in a plane normal to said axis, a

servomotor mechanically connected to pivot said quadrant and level and the rotor of said repeater, and means responsive to departure of the field and rotor of said repeater from a predetermined angular relation, and effective to 22 initiate rotation of said servomotor to thereby restore said relation.

15. In a system for elevating a gun mounted for manually-controlled elevation upon a trainable carriage, in response to the predicted output of a remote director, coarse and fine synchronous repeaters carried by said gun and adapted to repeat the respective field rotations of intergeared coarse and fine transmitters at said director, level indicatin means mounted upon said gun for pivotal movement about an axis parallel to the elevation axis of said gun and adapted to indicate the level position of a line in a plane normal to said axis, a servomotor connected to so move said level indicating means and the rotor of said fine repeater, amplifier means connected to control rotation of said servomotor, in response to relative rotation between the rotor of said fine repeater and its field, and synchronizer means adapted to assume control of said amplifier and including a two part circuit closer, one said part being mechanically connected for operation by said servomotor, and the other said part being mechanically connected for operation by said coarse repeater, whereby said gun is continuously properly elevated in accordance with the predicted output of said director when said gun is elevated so that said indicating means indicates a level position of said line.

16. In a system for training a gun to continuously engage a moving target, said gun being elcvatable about a normally horizontal axis carried by a trainable carriage, coarse and fine synchro-transformers on said carriage, each having a rotor and field coils, said coils being adapted to repeat the field rotations of the respective coarse and fine intergeared transmitters of a remote director, a panoramic telescope mounted upon said carriage and having an objective rotatable to move the line of sight of said telescope in azimuth independently of said gun, a two-phase servomotor, one phase of said servomotor being continuously energized, an amplifier having its output connected to energize the other phase of said servomotor and an input connected to be energized responsive to departure from a predetermined relation, of the resultant field and rotor of said fine synchro-transforme'r, a synchronizer comprising first and second relatively movable parts, said first part having spaced, opposed, first and second contacts, means operated by said servomotor to drive said first part and fine synchrotransformer rotor in the same ratio as said intergeared transmitters, said second part including a third contact adapted'to engage either of saidfirst and second contacts upon relative rotation of said parts in respectively opposite di- ,rections, a source of alternating voltage, connections adapted to apply said voltage in phase opposition to the input of said amplifier in response to engagement of said first or second contact by said third contact, and a geareddown mechanical drive between said fine synchro-transformer rotor and said objective.

17. In a system for training a gun mounted for elevation on a trainable carriage, and having manually-controlled training means including a rotatable shaft, a repeater having a rotor and field coils adapted for connection to repeat the field rotations of a transmitter at a remote director, a differential having one side connected to said shaft and a second side connected to drive said rotor, a milliammeter connected to be re- 23 sponsive to departure from a predetermined relation of the resultant field of the field coils and rotor of said repeater, and manually-adjustable means connected to operate the third side of said differential.

18. In a gun aiming system, a gun carriage trainable about a normally vertical axis, a cradle on said carriage, a gun in said cradle, means pivoting said cradle on said carriage for elevation about a normally horizontal trunnion axis, manually operable means to train said carriage, cradle and gun about said normally vertical axis, a sight carried by said carriage and having an eyepiece fixedly mounted thereon and an objective rotatable about a second normally vertical axis to rotate the line of sight of said sight in azimuth relatively to said gun, a repeater motor on said carriage, and a mechanical drive connecting said motor to said objective in fixed predetermined ratio.

19. In a system for aiming a gun mounted for movement in train and elevation about respective first and second mutually normal axes, sighting means carried by said gun for movement as a unit therewith in train, said sighting means having an objective part movable relatively to said gun about an axis parallel to said first axis to correspondingly angularly move the external line of sight thereof relatively to the gun, level means carried by said gun for movement as a unit therewith in elevation and pivotable relativelyto said gun about an axis parallel to said second axis, a remote director having outputs equal to the angles of train and elevation of the gun necessary to hit a moving target, first and second repeater motors connected to angularly move said objective part and said level means, respectively, relatively to the gun, and means including electrical telemetric connections between said director and said motors to operate the same in accordance with the respective outputs of said director.

20. In a gun data transmision system, a director including interconnected coarse and fine output transmitters, a gun, coarse and fine repeaters carried by said gun for training therewith, each said transmitter and repeater including a plurality of field coils and a rotor coil, cable means interconnecting the field coils of the coarse transmitter and repeater, cable means interconnecting the field coils of the fine transmitter and repeater, present predicted gun position indicating means carried by said gun and pivotable relatively thereto, a servo-motor mechanically connected to pivot said indicating means and to simultaneously rotate the rotor coil of said fine repeater, in synchronism, an amplifier having an output connected to control the rotation of said servo-motor and an input energized only in resopnse to departure from predetermined relation of the resultant field of the field coils of said fine repeater and its rotor.

21. In a, gun data transmission system, a director including interconnected coarse and fine output transmitters, a gun mounted for movement in train about a normally vertical first axis, a coarse repeater and a fine repeater carried by said gun for angular movement therewith, each said transmitter and repeater including a plurality of field coils and a rotor coil, cable means electrically interconnecting the field coils of said coarse transmitter and repeater, cable means electrically interconnecting the field coils of said fine transmitter and repeater, a panoramic line of sight device mounted on said gun for angular movement in train therewith, said device includ- 0 z; ing an objective head rotatable relatively to said gun about a second axis parallel with said first axis to corresponding angularly move the external line of sight of said sight, a servo-motor mechanically connected to rotate said objective head and to simultaneously rotate the rotor coil of said fine repeater, in synchronism, an amplifier having an output connected to control the rotation of said servo-motor and an input energized only in response to departure from predetermined relation of the resutlant field of the field coils of said fine repeater and its rotor.

22. The system recited in claim 21, and means 'for synchronizing said coarse and fine repeaters,

said means including a pair of opposed contacts driven at reduced rate by said fine repeater, a single contact driven by said coarse repeater and adapted to make contact with one or the other of said opposed contacts in response to predetermined lack of synchronism in a corresponding direction between said coarse and fine repeater rotors, and electrical connections between said contacts and servo-motor and including said amplifier for energizing said servo-motor to move said one of said opposed contacts out of engagement with said single contact,

23. In combination with a flexible gun having training means operable to move said gun about a normally vertical axis, a sight pivotally mounted upon said gun for movement as a unit therewith about said vertical axis only, and adapted to be adjusted to rotate its line of Sight relatively to said gun through substantially 366 in azimuth, a repeater motor on said gun and connected to said Sight to sorotate its line of sight, and telemetric control means remote from said gun and adapted to operate said repeater motor to rotate said line equally and oppositely to the movement in train necessary to continuously aim said gun to hit a moving target, whereby said gun may be continuously properly trained by operating said training means to maintain said line of sight directed upon a preselected fixed aiming point other than said target.

JOSEPH L. BORDEN, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,133,765 Voller Mar. 30, 1915 1,322,153 Wilson et al. Nov. 18, 1919 1,327,204 Henderson Jan. 6, 1920 1,374,144 Farrell et al Apr. 5, 1921 1,626,824 Hewlett et al. May 3, 1927 1,730,290 Petschenig et al. Oct. 1, 1929 1,936,442 Willard Nov. 21, 1933 2,010,397 Joyce Aug. 6, 1935 2,206,875 Chafee et a1 July 9, 1940 2,372,613 Svoboda Mar. 27, 1945 2,404,127 Ernst July 16, 1946 2,414,102 Hull et al Jan. 14, 1947 2,414,108 Knowles et a1 Jan. 14, 1947 2,419,886 Crooke Apr. 29, 1947 2,420,816 Davis May 20, 1947 2,432,772 Lear Dec. 16, 1947 2,463,687 Gittens Mar. 8, 1949 2,476,300 Holeschuh et al. July 19, 1949 2,478,398 Darr et al. Aug. 16, 1949 FOREIGN PATENTS Number Country Date 15,570 Netherlands Dec. 15, 1926 

